1. Field of the Invention
The present invention generally relates to electrical connectors, and more particularly to a connector having at least one contact grounded to the shell or housing of the connector.
2. Description of the Related Art
In many types of electrical connectors, it is desirable to provide grounding for one or more of the contacts directly to the shell of the connector. Such grounding is typically provided by using a screw to establish an electrical connection between the contact to be grounded and the shell of the connector. A hole is machined in the shell and in the insert that retains the contacts in the shell, and threads are tapped into the contact. Then the shell insert and contact are aligned and the screw inserted into the openings in the shell and insert, and threaded into the contact. Threading ensures engagement between the grounding contact and the screw, as well as between the head of the screw and the connector shell. Examples of this type of screw grounding arrangement are disclosed in U.S. Pat. Nos. 2,410,618, 4,113,333, 4,291,930, and 4,407,553.
There are several problems with the conventional screw-based grounding arrangement. First, the presence of an opening in the shell through which the screw is inserted may compromise the environmental sealing of the connector. Second, assembly of this type of connector is difficult because of the need to align holes in the insert and contact with the hole in the shell following insertion of the contact into the insert, and of the insert into the shell. Third, since the head of the screw is arranged on the outside surface of the shell, it can be inadvertently loosened so as to create a situation where the shell is not properly grounded.
An alternative arrangement that eliminates the need for a grounding screw is disclosed in U.S. Pat. No. 5,573,411. In the arrangement disclosed in this patent, a grounding wire contact pin is integrally formed with a grounding wire element that extends to the outer surface of an insert and forms an interference fit with an inside surface of the outer shell of the plug. While this arrangement eliminates the need for forming a screw hole in the outer shell of the plug, however, it has the disadvantage that it can only be used in situations where the contact pin and grounding element may be molded into the insert. Since the pin and grounding element are integrally formed inside the insert, they are difficult to manufacture with appropriate tolerances, greatly limiting applicability of this type of grounding arrangement. In addition, because the pin and grounding element are not molded into the insert, the entire insert assembly must be replaced if the contact or grounding element fails.